package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

final class IntBlockPool {

    public int[][] buffers = new int[10][];

    int bufferUpto = -1; // Which buffer we are upto
    public int intUpto = DocumentsWriter.INT_BLOCK_SIZE; // Where we are in head buffer

    public int[] buffer; // Current head buffer
    public int intOffset = -DocumentsWriter.INT_BLOCK_SIZE; // Current head offset

    final private DocumentsWriter docWriter;

    public IntBlockPool(DocumentsWriter docWriter) {
        this.docWriter = docWriter;
    }

    public void reset() {
        if (bufferUpto != -1) {
            if (bufferUpto > 0)
                // Recycle all but the first buffer
                docWriter.recycleIntBlocks(buffers, 1, 1 + bufferUpto);

            // Reuse first buffer
            bufferUpto = 0;
            intUpto = 0;
            intOffset = 0;
            buffer = buffers[0];
        }
    }

    public void nextBuffer() {
        if (1 + bufferUpto == buffers.length) {
            int[][] newBuffers = new int[(int) (buffers.length * 1.5)][];
            System.arraycopy(buffers, 0, newBuffers, 0, buffers.length);
            buffers = newBuffers;
        }
        buffer = buffers[1 + bufferUpto] = docWriter.getIntBlock();
        bufferUpto++;

        intUpto = 0;
        intOffset += DocumentsWriter.INT_BLOCK_SIZE;
    }
}
